Homing switch



F. JOHNSON ET AL March 15, 1955 HOMING SWITCH 2 Sheets-Sheet 1 Filed Feb. 18, 1952 y 3 r m M NR m? M N J 70 A L E 5% 8 March 15, 1955 JOHNSON ETAL 2,704,310

HOMING SWITCH Filed Feb. 18, 1952 2 Sheets-Sheet 2 FREDER/ a so 20 524 BY ,4;- ra/PNI r United States Patent HOMING SWITCH Frederick Johnson and Stuart Morrison, Cedar Rapids, Iowa, assignors to Collins Radio Company, Cedar Rapids, Iowa, a corporation of Iowa Application February 18, 1952, Serial No. 272,068 Claims. (Cl. 200-12) This invention relates in general to asystem which may be controlled from any one of a pluralityof locations such that when one of the control knobs 1s turned it assumes control of the controlled element.

It is oftentimes desirable to control the position of a shaft from a number of remote locations. For example, a radio transmitter might be located at a first position and have remote control units at other positions. It 1s advisable in general to have only one controlling point in use at a time so that the transmitter will not be confused by a number of commands received simultaneously.

It is an object of this invention therefore, to provide a shaft control system with remote controlling units located at a plurality of positions that they may ll'ldlvidually assume control of the controlled shaft.

Another object of this invention is found in the provision for control switches which automatically return to a home position when another switch is actuated.

Further features, objects and advantages of this invention will become apparent from the following description and claims when read in view of the drawing, in which:

Figure 1 illustrates a system according to this invention' Figure 2 is an exploded view of the controlling switch of this invention;

Figure 3 is a side view of the controlling switch;

Figure 4 is a suitable electrical circuit for operating a pair of controlling switches; and,

Figure 5 is a suitable electrical circuit for operating three controlling switches.

Figure 1 illustrates by way of example, a transmitter which may be controlled by a first switch 11 located at the transmitter site, or alternatively, by second and third switches 12 and 13 located at remote positions. Let it be assumed that each of the switches 11, 12 and 13 have a first home position which corresponds to the 01f position of the transmitter 10 and a number of other positions which correspond to a particular frequency setting of the transmitter 10.

The problem presented is to control the transmitter 10 from any of the three switch positions. In other words, if an operator at switch 12 turns it to a setting corresponding to 30 megacycles the transmitter is automatically tuned to this frequency. One position might turn the transmitter on, another one might put it on voice, or another might put it on CW. This is true even if the transmitter 10 may have been previously set to 20 megacycles by switch 11.

To accomplish the desired results applicant has developed a system wherein operation of any one of the control switches immediately returns all the other switches to a home position corresponding to the transmitter off-position so that only the switch being turned sends a command to the transmitter. If, subsequently, another control switch is operated the previous control switch will return to the home position and allow the new switch to assume command.

One of the switches such as 11, 12 and 13 is shown in Figure 3 and comprises a knob 14 which is mounted on a shaft 16 which passes through a plate 17 that is mounted to a second plate 18 by standoffs 19. A switch 21 is of the wafer type and has a stationary disc 22 that is mounted to the plate 17 and a rotary portion 23 which is mounted on the shaft 16. The switch 21 is the relay control switch. A second wafer switch 25 is mounted on shaft 16 and is the function control switch.

2,704,310 Patented Mar. 15, 1955 It might be connected as the control switch of a system according to Patent No. 2,476,673. As is best shown in Figure 2 the shaft 16 has a fiat portion 24 that passes through a slot formed in a lever arm 26. The lever arm 26 engages a second lever arm 27 that is mounted on a second shaft 28.

A third plate 29 is mounted to plate 18 by standofi's 31 and the shaft 28 passes therethrough. An arcuate slot 66 is formed in the plate 29 adjacent the shaft 28. A coil spring 32 has an end lug 33 'which is received over a pin 34 mounted on the plate 29. An internal end loop 36 is formed on the spring. The shaft 28 passes through a center opening 37 in the spring adjacent the end loop 36.

The shaft 28 passes through plate 18 and has a toothed stop-wheel 39 mounted on its end. A pin 41 extends transversely of the stop-wheel 39 through an arcuate slot in the plate 18 and passes through the internal holding loop 36 of the spring.

A pawl 42 is pivotally supported on the plate 18 and engages the toothed stop-wheel 39 so that it can turn in only one direction when they are engaged.

An electrical relay, designated generally as 43, is mounted to the plate 18 by holding means 44 and has an armature 46 that engages a projection 47 on the pawl 42 so as to lift it out of engagement with the toothed stop-wheel when the relay is energized. A pair of leads 48 and 49 are connected to the relay 43. A spring 51 is mounted to the plate 29 so as to engage the lever arm 27 when it is released.

In operation, the knob 14 moves the lever arm 26 and the rotary disc 23 through the shaft 16. The lever arm 26 engages the arm 27 so as to move it to any of a number of positions. The switch 21 contains a suitable detent so that the shaft 16 moves in distinct increments corresponding to particular settings. It is to be noted that the arm 26 moves the arm 27 in one direction only. Thus, if it is desired to move the arm 27 from a number six position to a number two position the knob 14 must be returned to the home or zero position which energizes the relay 43 so as to release the stop-wheel 39 which returns arm 27 to the home position due to the action of the spring 32.

Figure 4 illustrates a circuit for controlling the relays 43 where two controlling switches are used.

It is to be remembered that whenever a switch is turned from the home position it is desired to return all other switches to the home position. The relay 43 returns the individual switches to their home position and when a switch is turned it will close the relay circuits if two switches are away from home.

With reference to Figure 4, a person located at station A may turn the knob 14-a to control the transmitter. The wafer-type switch 21-a comprises an annular member 52-a which has a gap 53-a. A number of contacts 54-11 are mounted about the disc 52-0. The coils of relays 43-a and 43-h are connected in parallel and one side of the relays 43-a and 43-12 are connected to a short contact 56-a which is engageable with disc 52-a in all positions except when the gap 53-41 is adjacent it. The other side of the relay coils 43-11 and 43-12 are connected to a short contact 56-12 which is engageable with the disc 52-11 in all positions except when the gap 53-h is adjacent it.

A suitable voltage source, as for example, 28 volts D. C. has its positive side connected to a second contact 57-a which engages the disc 52-a at all times. The negative side of the voltage supply is connected to a contact 57-b which engages the disc 52-]; at all times. This switching arrangement closes the armature circuits of the relays 43-a and 43-1) at any time when both contacts 56-a and 56-h engage their respective discs 52-a and 52-12. When only one of the contacts 56-a or 56-17 engages its respective disc the relay circuits are not closed.

A circuit for controlling three switches is illustrated in Figure 5. The switches are designated generally as 21-a, 21-b and 21-0, and an additional disc 58-a, 58-b and 58-c is mounted on the same shaft with the discs 52 so that they turn together. The discs 58 have a broken portion and a gap 59. One side of each relay coil 48 is connected to the positive terminal of a suitable voltage source and the other side 49 of each relay coil is connected, respectively, to contacts 56 which engage the discs 52 at all times except when the gap is in line with them.

The negative side of the voltage source is connected to wiper contacts 61a, 61-1; and 61c respectively, which engage the discs 58 at all times except when the broken portion is opposite them. Second wiper contacts 62 and 63 respectively, are mounted adjacent each disc 58 with the contacts 62 of a length such that they engage the discs 58 except when the gap 53 or the open portion is opposite them. The contacts 63 engage the discs 58 at all times except when the open portion is opposite them.

The contacts 62-11, 63-h and 57-c are connected together. The contacts 63-0, 57-b and 62c are connected together. The contact 62-!) is connected to contacts 57-a and 63-0.

This circuitry has the characteristic that when any pair of the knobs 14a, l4-b or 14-0 are moved away from the home position corresponding to that shown in Figure 5 the relays 43-11, 43b and 43-c will be energized and allow the switches and the knobs to return to a home position. It is to be realized, of course, that the knob being manually adjusted will not return to a home position because it is held by the operator, and after all other switches have returned to the home position it will stay in the new set position when released.

It is seen that this apparatus provides means for taking control at any one of a plurality of positions. When any of the control knobs 14 are rotated the controlled elemen s actuated. The switches may be connected to a suitable electrical control circuit which positions the shaft to control the transmitter, as for example, an auto-positioner such as described in Patent No. 2,476,673. The connections for switches 25 are not shown because they are shown in detail in the referenced patent. Reference may be made to this patent for a detailed descrip' tion. A number of control circuits may be used and the one discussed in Patent No. 2,476,673 is used as an example only.

Although this invention has been described with respect to particular embodiments thereof, it is not to be so limited as changes and modifications may be made therein which are within the full intended scope of the invention as defined by the appended claims.

We claim:

1. A switch adapted for use with other switches and which will return to a home position at any time any of the other switches are moved away from the home position comprising, a first base plate rotatably supporting a first shaft, a control knob attached to one end of said first shaft, a lever arm attached to said first shaft, a second shaft, a second plate rotatably supporting the second shaft, a toothed stop-wheel connected to said second shaft, a pawl engageable with said toothed stopwheel and pivotally supported by said second plate, an electromagnetic relay connected to said second plate and engageable with said pawl, a flexible means connected to said second shaft to spring bias it for one direction of rotation, and a second lever arm connected to said second shaft and engageable with said first lever arm.

2. A control switch which returns to a home position when any other control switch is moved away from the home position comprising, three end plates, a first shaft rotatably supported by the first plate, a control knob at one end of said first shaft, a first lever arm attached to said first shaft, a second shaft rotatably supported by the second and third end plates, at toothed stop-wheel mounted on said second shaft, a pawl pivotally supported by the second end plate and engageable with the toothed stop-wheel, a second lever arm attached to the second shaft and engageable with the first lever arm, a coil spring mounted about said second shaft between the second and third end plates and biasing said second shaft for one direction of rotation, an electromagnetic means mounted to said second end plate adjacent said pawl and engageable therewith, and an electromagnetic control circuit connected to said electromagnetic means and said control switches.

3. A shaft control mechanism comprising, three end plates, a first shaft rotatably supported by one of said end plates, a knob connected to one end of the first shaft, a first lever arm connected to said first shaft, a switching means connected to said first shaft, a second shaft rotatably supported by the second and third end plates, a stop-wheel attached to said second shaft, a pawl pivotally supported by said second end plate and engageable with the stop-wheel, electromagnetic means connected to the second end plate and the pawl to control its position relative to the stop-Wheel, spring means connected to said second shaft and said third end plate for spring biasing the second shaft in one direction, and a transverse pin attached to said stop-wheel and extending through arcuate slots formed in the second and third end plates.

4. A controlled switch comprising, first, second and third end plates connected together by suitable stand-offs, a first shaft rotatably supported by the first end plate, a knob attached to one end of said shaft, a lever arm attached to the other end of said first shaft, 21 second shaft rotatably supported by the second and third end plates, spring biasing means attached to the third end plate and to the second shaft so as to bias it for a particular direction of rotation, a second lever arm mounted on the second shaft and engageable with the first lever arm on the first shaft, a pawl pivotally supported by the third end plate, a toothed stop wheel rotatably supported by the second shaft and engageable with the pawl, a relay attached to the second end plate, and a pair of wafer switches with their stators attached to the first end plate and their rotors connected to the first shaft.

5. A control switch comprising, first, second, and third end plates connected together with stand-offs, a first shaft rotatably supported by the first end plate, a lever arm attached to said first shaft, a knob connected to said first shaft, a second shaft rotatably supported by the second and third end plates, :1 second lever arm connected to the second shaft between the first and second end plates and engageable with the first lever arm, a toothed stop-wheel attached to said second shaft, a pawl pivotally supported by the third end plate and engageable with the toothed stop-wheel, electromagnetic means mounted on the third end plate and engageable with the pawl, a spring attached to the second shaft and the second end plate to bias the second shaft to a home position, and a stop means mounted on the second end plate and engageable with the second lever arm to limit its angular motion.

References Cited in the file of this patent UNITED STATES PATENTS 2,451,150 Brian Oct. 12, 1948 2,570,481 Priesmeyer Oct. 9, 1951 2,582,270 Olson Ian. 15, 1952 

